Alphanumeric (sometimes seen as alphameric) is a term encompassing all the letters in a given language set as well as the numerals. In layouts designed for English language users, alphanumeric characters are those comprised by the combined set of the 26 alphabetic characters, A to Z, and the 10 Arabic numerals, 0 to 9.
For some computer purposes, such as file naming, alphanumeric characters are strictly limited to the 26 alphabetic characters and 10 numerals; however, for other usages, such as programming, other keyboard symbols are sometimes permitted. In some usages, the alphanumeric character set may include both upper and lower case letters, punctuation marks, and symbols (such as @, &, and *, for example). For languages other than English, alphanumeric characters include letter variations such as é and ç.
The mishmash of letters and numerals used for texting abbreviations is sometimes referred to as alphanumerish. As is the case with the term alphanumeric, alphanumerish can be expanded to include other characters. The grawlix, for example, which represents a non-specific profanity, is generally made up of typographical symbols that don't include either letters or numerals, but it might be considered an alphanumerish word nevertheless.